GCM: fix mode and padding set
Since "GCM" was renamed to "AES/GCM/NoPadding" to correspond to the
StandardNames document, the mode and padding weren't being set via the
Cipher#init call since it assumed the CipherSpi already knew its mode
and padding.
(cherry picked from commit 65581d2bbf27de395c221f5f7f4fd93cbab091ff)
Bug: 22611918
Change-Id: Ib85438a1c95ffda526dbbac8793b04ff02d40fcc